Table 4.
Preterm delivery results for daily bottled, cold tap, total tap, and total water intake
| Follow-up data | Average of baseline and follow-up data |
|||
|---|---|---|---|---|
| Exposure | n (%) | Unadjusted RR (95% CI) | Adjusted RR (95% CI)a | Adjusted RR (95% CI)a |
| Bottled water | ||||
| None | 483 (25%) | 1 | 1 | 1 |
| Any | 1458 (75%) | 1.2 (0.9, 1.8) | 1.2 (0.8, 1.8) | 0.8 (0.5, 1.4) |
| Cold tap water (ounces)b | ||||
| 0-27 | 472 (24%) | 1 | 1 | 1 |
| > 27-53 | 494 (25%) | 0.8 (0.5, 1.2) | 0.8 (0.5, 1.3) | 0.9 (0.6, 1.4) |
| > 53-91 | 485 (25%) | 0.9 (0.6, 1.3) | 0.9 (0.6, 1.4) | 0.9 (0.6, 1.4) |
| > 91 | 490 (25%) | 0.8 (0.5, 1.1) | 0.8 (0.5, 1.3) | 1.0 (0.6, 1.5) |
| Per 20 ounce | 1.0 (0.9, 1.0) | 0.9 (0.7, 1.3) | 0.9 (0.6, 1.3) | |
| Total tap water (ounces)b | ||||
| 0-30 | 493 (25%) | 1 | 1 | 1 |
| > 30-61 | 483 (25%) | 0.8 (0.5, 1.2) | 0.8 (0.5, 1.2) | 1.0 (0.6, 1.5) |
| > 61-96 | 535 (28%) | 0.7 (0.5, 1.1) | 0.8 (0.5, 1.2) | 1.2 (0.8, 1.9) |
| > 96 | 429 (22%) | 0.9 (0.6, 1.3) | 1.0 (0.6, 1.5) | 0.9 (0.6, 1.4) |
| Per 20 ounce | 1.0 (0.9, 1.0) | 0.9 (0.7, 1.2) | 0.9 (0.6, 1.3) | |
| Total water (ounces)b | ||||
| 0-51 | 491 (25%) | 1.0 | 1.0 | 1.0 |
| > 51-78 | 478 (25%) | 1.0 (0.7, 1.6) | 1.2 (0.7, 1.9) | 1.1 (0.7, 1.7) |
| > 78-114 | 481 (25%) | 1.0 (0.7, 1.6) | 1.1 (0.7, 1.8) | 1.0 (0.6, 1.5) |
| > 114 | 478 (25%) | 1.2 (0.8, 1.8) | 1.4 (0.9, 2.2) | 1.2 (0.8, 1.9) |
| Per 20 ounce | 1.0 (1.0, 1.1) | 1.1 (0.9, 1.4) | 1.1 (0.8, 1.5) | |
aAdjusted for race, education level, annual household income, smoking, pre-pregnancy BMI, vitamin use, parity, employed during last 4 months, infant gender, and study site
bCategorical exposure cutpoints for average data results were slightly higher than the follow-up data
BMI= body mass index; RR= risk ratio